1. Field of the Invention
The invention herein pertains generally to the field of engine powered skateboards.
2. The Background Art
Skateboards are normally built with front and back wheels rotatably mounted to a platform. To gain momentum, the skateboard rider stands on the platform with one foot and propels the skateboard by placing the other foot on the ground and pushing. The rider stops the skateboard either by dragging a foot or with the pivot-and-drag method. The pivot-and-drag method is executed by pivoting the platform on either the front or rear wheels so that the opposite wheels lift off the ground. This pivoting causes the end of the platform nearest the wheels that remain on the ground to drag on the ground, stopping the skateboard through frictional drag. The pivoting technique is further used to engage in small radius turns and twirling maneuvers. A skateboard rider may gain additional momentum by riding the skateboard downhill or by being towed by another vehicle.
The common methods for gaining additional momentum have inherent problems and dangers. Hills compatible with the use of a skateboard are not always available. When they are the rider desiring to skateboard down the hill again must return to the top after reaching the bottom. The dangers and limitations of being towed by another vehicle are also significant, especially if the skateboard rider is towed by an automobile.
To solve these problems, it has been desirable to attach a motor or an engine to the skateboard which the driver can control. A number of different approaches have been made with varying degrees of limited success. The usual approach in the art has been to attach an engine or motor to the skateboard coupled to one or both of the back wheels. This approach requires that the skateboard undergo substantial alteration of the skateboard's back wheels or platform. Additional problems arise under this approach with regard to the steerability and stability of the skateboard, as the dynamics for turning, stopping, and balance of the skateboard are substantially altered or limited when one or more of the back wheels are coupled to an engine.
Another approach, as seen in U.S. Pat. No. 4,073,356, has been to elongate the platform of the skateboard, open a hole in the center of the platform, and attach a fifth wheel to the platform; with the fifth wheel extending through the platform to where it is coupled to a motor. This approach has a number of limitations, including: the rider is required to straddle the motor and drive wheel; the traction of the fifth wheel depends upon the unnatural shifting of the weight distribution of the person on the skateboard; a specialized elongated skateboard construction is required to attach the motor and fifth wheel to the skateboard; and, the engine and drive wheel being mounted equidistant from the front and back wheels for the cantilever effect of the flexible platform makes the skateboard difficult to stop in the pivot-and-drag method of skateboard riders because the engine and wheel assembly must be lifted into the air.
Vibrations to the engine and drive wheel assembly have been an additional source of problems for engine or motor driven skateboards. The vibrations caused by the engine and the vibrations, shocks, and bumps transmitted from the ground through the driven wheel to the engine cause instability in engine or motor driven skateboards. This instability problem has not been previously addressed with regard to skateboards. No force absorption means is taught in the prior art with regard to engine or motor driven skateboards.
To compensate for the instability of engine or motor driven skateboards, the prior art teaches a number of different throttle controls using flexible cables or wires. The belief has been that the hands had to be used as "counter weights" which the skateboard rider was required to throw upwards and sideways to maintain balance on the skateboard. So, the effort has been to make the controls increasingly flexible in order to allow the hands to flail around.